EP0608474B1 - Pixel resolution enhancement employing encoded dot size control - Google Patents
Pixel resolution enhancement employing encoded dot size control Download PDFInfo
- Publication number
- EP0608474B1 EP0608474B1 EP93112664A EP93112664A EP0608474B1 EP 0608474 B1 EP0608474 B1 EP 0608474B1 EP 93112664 A EP93112664 A EP 93112664A EP 93112664 A EP93112664 A EP 93112664A EP 0608474 B1 EP0608474 B1 EP 0608474B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- laser
- pixel
- image
- engine controller
- color
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K15/00—Arrangements for producing a permanent visual presentation of the output data, e.g. computer output printers
- G06K15/02—Arrangements for producing a permanent visual presentation of the output data, e.g. computer output printers using printers
- G06K15/12—Arrangements for producing a permanent visual presentation of the output data, e.g. computer output printers using printers by photographic printing, e.g. by laser printers
- G06K15/1204—Arrangements for producing a permanent visual presentation of the output data, e.g. computer output printers using printers by photographic printing, e.g. by laser printers involving the fast moving of an optical beam in the main scanning direction
- G06K15/1223—Resolution control, enlarging or reducing, edge or detail enhancement
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K2215/00—Arrangements for producing a permanent visual presentation of the output data
- G06K2215/0002—Handling the output data
- G06K2215/004—Generic data transformation
- G06K2215/006—Anti-aliasing raster data
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K2215/00—Arrangements for producing a permanent visual presentation of the output data
- G06K2215/0082—Architecture adapted for a particular function
- G06K2215/0094—Colour printing
Definitions
- This invention relates to raster pixel image printers and, more particularly, to a system for improving the resolution of pixels which reside at edges of image features.
- a desired image is created by causing a laser to be modulated in accordance with a bit pattern stored in an image bit map.
- the modulated laser beam is scanned across a charged surface of a photosensitive drum in a succession of raster scan lines. Each scan line is divided into pixel areas and the modulated laser beam causes some pixel areas to be exposed to a light pulse and some not, thus causing a pattern of overlapping pixels on each scan line.
- the photosensitive drum is discharged, so that when it is subsequently toned, the toner adheres to the discharged areas and is repelled by the still charged areas. Subsequently, the toner is transferred to paper and fixed in the known manner.
- image edges that are either not parallel to the raster scan direction or not perpendicular to it appear stepped.
- Tung shows a character generator that produces a bit map of image data and inputs that bit map into a first-in first-out (FIFO) data buffer.
- a fixed subset of the buffer stored bits forms a sampling window through which a selected block of the bit map image data may be viewed (for example, a 9 x 9 block of pixels with the edge pixels truncated).
- the sampling window contains a center bit cell which changes on each shift of the image bits through the FIFO buffer.
- the sampling window views successive bit patterns formed by pixels located at the window's center bit cell and its surrounding neighbor bit cells. Each bit pattern formed by the center bit and its neighboring bits is compared in a matching network with prestored templates.
- a modulation signal is generated that causes the laser beam to alter the center pixel configuration.
- the center pixel is made smaller than a standard unmodified bit map pixel and is possibly moved within the confines of pixel cell.
- the pixel size alteration is carried out by modulating the laser contained in a "laser print engine" of the printer.
- the system taught by Tung is now generally referred to as Resolution Enhancement Technology (RET) and enables substantially improved image resolutions to be achieved.
- RET Resolution Enhancement Technology
- US-A-5 029 108 discloses an edge enhancement apparatus where the edge enhancement sensor outputs a multi-bit command to modulate the laser of the laser print engine.
- the circuitry that modulates the laser beam is directly accessible to the RET circuitry.
- variable length pulses generated by an RET circuit can be directly applied to modulate pixel size and to achieve the enhanced image resolution.
- direct access is, in general, no longer available.
- the laser's drive circuits are not available for external connection to the RET's variable width pulse generator so as to enable modification of pixel size and positioning.
- a processor is employed as the laser engine controller.
- the processor enables the necessary print engine control functions to be carried out in correct time order, while assuring accurate registration of succeeding color planes.
- Resolution Enhancement Technology as taught by Tung, has not been heretofore accomplished with a color printer.
- a color laser printer and a method according to the invention are set out in claims 1 and 7 respectively.
- Fig. 1 is a block diagram of a laser printer incorporating the invention.
- Fig. 2 is a waveform diagram helpful in understanding the operation of the laser printer of Fig. 1.
- Fig. 3 is a further waveform diagram illustrating commands issued by the format controller of Fig. 1 and the resulting pulsewidth modulation signals that emanate from the laser engine controller.
- a host processor 10 transmits image data to a printer 12 (schematically shown within the dotted line).
- the image data is received via input/output (I/O) module 14 and is temporarily stored in random access memory (RAM) 16 under control of central processing unit (CPU) 18. Communications within printer 12 occur over bus (or busses) 20.
- a format controller 22 receives image data from RAM 16 and under control of CPU 18, formats the image data into raster-arranged color plane bit maps.
- Each bit map plane is a raster arranged image of pixels of a single color.
- Format controller 22 may contain a single color plane bit map (with the remainder planes being contained in RAM 16 until ready for printing), or it may be provided with sufficient storage capacity to store all planes of an image, i.e., yellow, magenta, cyan and black planes. Format controller 22 further contains the software and circuitry for performing edge pixel enhancement procedures described in the aforementioned Tung patent. Edge enhancement circuitry 24 essentially examines a window of pixels within a bit map plane and determines the presence or absence of a match between the pattern of pixels in the window and a stored template. If a match is found, an appropriate signal is generated to enable adjustment of the configuration of the window's center pixel so as to enhance the ultimate edge representation when the bit map is printed.
- Engine controller 26 further includes a laser control circuit 28 that enables time modulation of the output pulses fed from engine controller 26 to laser drive circuit 30.
- Laser control circuit 28 operates in conjunction with engine controller 26 so that, as individual pixel signals are fed to laser drive circuit 30, they are appropriately time modulated so as to both accurately represent the bit map in format controller 22, and exhibit a configuration in accordance with the determinations of edge enhancement circuitry 24.
- Laser drive circuit 30, in response, modulates the signal of a laser in laser engine 32 so that electrostatic printing may be accomplished.
- Engine controller 26 provides a plurality of additional outputs to laser engine 32 in order to control the movement of various motors, gears, etc. to enable both paper and laser beam movement. Those interconnections are not shown to avoid over-complication of the view.
- Engine controller 26 generates the principal timing signals (under control of CPU 18) that enable operation of both format controller 22 and laser drive circuit 30.
- Engine controller 26 provides on output line 34, a PSYNC signal that synchronizes the printer's yellow, magenta, cyan and black, color bit map successive print operations.
- the PSYNC signal 50 for the yellow bit plane is shown in expanded form by trace 51.
- Engine controller 26 during the active state of PSYNC (PSYNC is active in the down state), provides a plurality of raster line synchronization pulses LSYNC on output line 36. Each LSYNC pulse occurs at the commencement of a raster scan line and causes the output of bit states representing pixels of a raster scan line. Subsequent to each LSYNC pulse, a pixel clock pulse 52 PCLK is produced, one for each pixel on the raster scan line. PCLK signals 52 are passed, via line 38, from engine controller 26 to format controller 22.
- Format controller 22 in response "turns around” each PCLK signal 52 and returns it to engine controller 26 as a video clock signal VCLK 54. Format controller 22 also emplaces on output line 42, data levels 56 VDATA that are representative of the pixel bit states.
- the data levels appearing on output line 42 represent actual pixel data and, in the case shown in Fig. 2, represent the pixel data for the yellow plane.
- pixel data is transmitted similarly.
- each pixel data pulse 56 (VDATA) is impressed on output line 42 from format controller 22, a five bit command signal is applied to RVDATA line 44 from edge enhancement circuitry 24.
- the RVDATA command indicates to laser control circuitry 28 whether the laser in laser engine 32 should be gated on, and if yes, whether the output pulse from engine controller 26 should provide for a full laser pulse or should be otherwise modulated for edge enhancement purposes.
- Trace 50' is the expanded yellow plane LSYNC pulse and trace 52' shows the PCLK signals fed from engine controller 26 to format controller 22.
- Trace 54' represents VCLK signals that are fed back by format controller 22 to engine controller 26 after a short delay t.
- VDATA 56' Upon the rise of each VCLK signal, video data VDATA 56' is applied to line 42 and is latched in engine controller 26 upon the negative going shift of each VCLK signal 52'. In such manner, each pixel value is appropriately entered into engine controller 26. Simultaneously, a five bit RVDATA command 58' is applied via RVDATA line 44 to laser controller 28 so that appropriate modulation (if necessary) can be applied to the latched pixel data.
- RVDATA commands are preferably 5 bit values that define a particular modulation signal to be outputed from engine controller 26 to laser drive circuit 30.
- Each RVDATA command enables a particular modulation time to be applied to laser drive circuit 30, so that it is capable of causing the printing of pixels of a variety of sizes, oriented at a plurality of positions within each pixel site.
- certain RVDATA commands cause modulation signals to be applied (to laser drive circuit 30) that cause the size of a pixel to be varied by tenths of a pixel cell site. Five of ten 5 bit data sets for accomplishing the 1/10 modulation are shown in Fig. 3.
- a pixel can also be modulated so that it is printed starting at either the left or right side of a pixel all site and extends a part of the way towards the other extremity of the pixel cell site.
- a full pixel can be printed or a left 1/5, 2/5, 3/5 or 4/5 of a pixel can be printed.
- the right 1/5, 2/5, 3/5 or 4/5 of a pixel can similarly be printed under control of an appropriate 5 bit RVDATA command.
- format controller 22 in combination with edge enhancement circuit 24 passes 5 bit edge enhancement commands RVDATA to engine controller 26.
- Those commands enable engine controller 26 and laser control 28 to output variable time pulses that modulate the output from laser drive circuit 30.
- laser engine 32 is enabled to produce a plurality of pixel sizes, with altered positions within a pixel all site.
- the command structure enables the modulation function to be accomplished using an already available modulation facility within engine controller 26 (laser control 28). No direct access is required to laser drive circuit 30 by format controller 22.
Description
- This invention relates to raster pixel image printers and, more particularly, to a system for improving the resolution of pixels which reside at edges of image features.
- In laser printers, a desired image is created by causing a laser to be modulated in accordance with a bit pattern stored in an image bit map. The modulated laser beam is scanned across a charged surface of a photosensitive drum in a succession of raster scan lines. Each scan line is divided into pixel areas and the modulated laser beam causes some pixel areas to be exposed to a light pulse and some not, thus causing a pattern of overlapping pixels on each scan line. Where a pixel area is illuminated, the photosensitive drum is discharged, so that when it is subsequently toned, the toner adheres to the discharged areas and is repelled by the still charged areas. Subsequently, the toner is transferred to paper and fixed in the known manner. As a result of the images's pixel configuration, image edges that are either not parallel to the raster scan direction or not perpendicular to it appear stepped.
- The prior art has attempted, in a variety of ways, to overcome the stepped appearance of pixel image edges. One of the more widely used techniques is described in U.S. Patent 4,847,641 to Tung, assigned to the Assignee of this application.
- Tung shows a character generator that produces a bit map of image data and inputs that bit map into a first-in first-out (FIFO) data buffer. A fixed subset of the buffer stored bits forms a sampling window through which a selected block of the bit map image data may be viewed (for example, a 9 x 9 block of pixels with the edge pixels truncated). The sampling window contains a center bit cell which changes on each shift of the image bits through the FIFO buffer. As the serialized data is shifted, the sampling window views successive bit patterns formed by pixels located at the window's center bit cell and its surrounding neighbor bit cells. Each bit pattern formed by the center bit and its neighboring bits is compared in a matching network with prestored templates. If a match occurs - indicating that the center bit resides at an image edge and that the pixel it represents can be altered so as to improve the image's resolution, a modulation signal is generated that causes the laser beam to alter the center pixel configuration. In general, the center pixel is made smaller than a standard unmodified bit map pixel and is possibly moved within the confines of pixel cell. The pixel size alteration is carried out by modulating the laser contained in a "laser print engine" of the printer. The system taught by Tung is now generally referred to as Resolution Enhancement Technology (RET) and enables substantially improved image resolutions to be achieved.
- US-A-5 029 108 discloses an edge enhancement apparatus where the edge enhancement sensor outputs a multi-bit command to modulate the laser of the laser print engine.
- In laser printers that produce black/white images, the circuitry that modulates the laser beam is directly accessible to the RET circuitry. As a result, variable length pulses generated by an RET circuit can be directly applied to modulate pixel size and to achieve the enhanced image resolution. However, in color laser printers, such direct access is, in general, no longer available. In other words, the laser's drive circuits are not available for external connection to the RET's variable width pulse generator so as to enable modification of pixel size and positioning.
- In a color printer, i.e. one which prints successive yellow, magenta, cyan and black "planes", a processor is employed as the laser engine controller. The processor enables the necessary print engine control functions to be carried out in correct time order, while assuring accurate registration of succeeding color planes. To the inventor's knowledge, Resolution Enhancement Technology, as taught by Tung, has not been heretofore accomplished with a color printer.
- Accordingly, it is an object of this invention to provide for the incorporation of Resolution Enhancement Technology into a color laser printer.
- It is a further object of this invention to incorporate Resolution Enhancement Technology into a laser printer without requiring direct access to laser drive circuits.
- It is yet another object of this invention to implement Resolution Enhancement Technology in a color laser printer, without requiring additional circuitry.
- A color laser printer and a method according to the invention are set out in
claims 1 and 7 respectively. - Fig. 1 is a block diagram of a laser printer incorporating the invention.
- Fig. 2 is a waveform diagram helpful in understanding the operation of the laser printer of Fig. 1.
- Fig. 3 is a further waveform diagram illustrating commands issued by the format controller of Fig. 1 and the resulting pulsewidth modulation signals that emanate from the laser engine controller.
- In Fig. 1, a
host processor 10 transmits image data to a printer 12 (schematically shown within the dotted line). The image data is received via input/output (I/O)module 14 and is temporarily stored in random access memory (RAM) 16 under control of central processing unit (CPU) 18. Communications withinprinter 12 occur over bus (or busses) 20. Aformat controller 22 receives image data fromRAM 16 and under control ofCPU 18, formats the image data into raster-arranged color plane bit maps. Each bit map plane is a raster arranged image of pixels of a single color. -
Format controller 22 may contain a single color plane bit map (with the remainder planes being contained inRAM 16 until ready for printing), or it may be provided with sufficient storage capacity to store all planes of an image, i.e., yellow, magenta, cyan and black planes.Format controller 22 further contains the software and circuitry for performing edge pixel enhancement procedures described in the aforementioned Tung patent.Edge enhancement circuitry 24 essentially examines a window of pixels within a bit map plane and determines the presence or absence of a match between the pattern of pixels in the window and a stored template. If a match is found, an appropriate signal is generated to enable adjustment of the configuration of the window's center pixel so as to enhance the ultimate edge representation when the bit map is printed. - Overall control of
laser engine 32 is accomplished byengine controller 26 and an included microprocessor.Engine controller 26 further includes alaser control circuit 28 that enables time modulation of the output pulses fed fromengine controller 26 tolaser drive circuit 30.Laser control circuit 28 operates in conjunction withengine controller 26 so that, as individual pixel signals are fed tolaser drive circuit 30, they are appropriately time modulated so as to both accurately represent the bit map informat controller 22, and exhibit a configuration in accordance with the determinations ofedge enhancement circuitry 24.Laser drive circuit 30, in response, modulates the signal of a laser inlaser engine 32 so that electrostatic printing may be accomplished. -
Engine controller 26 provides a plurality of additional outputs tolaser engine 32 in order to control the movement of various motors, gears, etc. to enable both paper and laser beam movement. Those interconnections are not shown to avoid over-complication of the view. - Referring to the waveform diagrams shown in Figs. 2 and 3, the operation of the system of Fig. 1 will be described.
Engine controller 26 generates the principal timing signals (under control of CPU 18) that enable operation of bothformat controller 22 andlaser drive circuit 30.Engine controller 26 provides onoutput line 34, a PSYNC signal that synchronizes the printer's yellow, magenta, cyan and black, color bit map successive print operations. - In Fig. 2, the
PSYNC signal 50 for the yellow bit plane is shown in expanded form bytrace 51.Engine controller 26, during the active state of PSYNC (PSYNC is active in the down state), provides a plurality of raster line synchronization pulses LSYNC onoutput line 36. Each LSYNC pulse occurs at the commencement of a raster scan line and causes the output of bit states representing pixels of a raster scan line. Subsequent to each LSYNC pulse, apixel clock pulse 52 PCLK is produced, one for each pixel on the raster scan line. PCLKsignals 52 are passed, vialine 38, fromengine controller 26 toformat controller 22.Format controller 22, in response "turns around" eachPCLK signal 52 and returns it toengine controller 26 as a videoclock signal VCLK 54.Format controller 22 also emplaces onoutput line 42,data levels 56 VDATA that are representative of the pixel bit states. The data levels appearing onoutput line 42 represent actual pixel data and, in the case shown in Fig. 2, represent the pixel data for the yellow plane. During succeeding scan times (i.e. during magenta, cyan andblack PSYNC pulses - At the same time each pixel data pulse 56 (VDATA) is impressed on
output line 42 fromformat controller 22, a five bit command signal is applied to RVDATAline 44 fromedge enhancement circuitry 24. The RVDATA command indicates tolaser control circuitry 28 whether the laser inlaser engine 32 should be gated on, and if yes, whether the output pulse fromengine controller 26 should provide for a full laser pulse or should be otherwise modulated for edge enhancement purposes. - The LSYNC, PCLK, VCLK, VDATA and RVDATA signals are shown in expanded form in the lower section of Fig. 2. Trace 50' is the expanded yellow plane LSYNC pulse and trace 52' shows the PCLK signals fed from
engine controller 26 to formatcontroller 22. Trace 54' represents VCLK signals that are fed back byformat controller 22 toengine controller 26 after a short delay t. - Upon the rise of each VCLK signal, video data VDATA 56' is applied to
line 42 and is latched inengine controller 26 upon the negative going shift of each VCLK signal 52'. In such manner, each pixel value is appropriately entered intoengine controller 26. Simultaneously, a five bit RVDATA command 58' is applied viaRVDATA line 44 tolaser controller 28 so that appropriate modulation (if necessary) can be applied to the latched pixel data. - As shown in Fig. 3, RVDATA commands are preferably 5 bit values that define a particular modulation signal to be outputed from
engine controller 26 tolaser drive circuit 30. Each RVDATA command enables a particular modulation time to be applied tolaser drive circuit 30, so that it is capable of causing the printing of pixels of a variety of sizes, oriented at a plurality of positions within each pixel site. For instance, certain RVDATA commands cause modulation signals to be applied (to laser drive circuit 30) that cause the size of a pixel to be varied by tenths of a pixel cell site. Five of ten 5 bit data sets for accomplishing the 1/10 modulation are shown in Fig. 3. A pixel can also be modulated so that it is printed starting at either the left or right side of a pixel all site and extends a part of the way towards the other extremity of the pixel cell site. Thus, a full pixel can be printed or a left 1/5, 2/5, 3/5 or 4/5 of a pixel can be printed. In a similar manner, the right 1/5, 2/5, 3/5 or 4/5 of a pixel can similarly be printed under control of an appropriate 5 bit RVDATA command. - In the above described manner,
format controller 22 in combination withedge enhancement circuit 24passes 5 bit edge enhancement commands RVDATA toengine controller 26. Those commands enableengine controller 26 andlaser control 28 to output variable time pulses that modulate the output fromlaser drive circuit 30. In response,laser engine 32 is enabled to produce a plurality of pixel sizes, with altered positions within a pixel all site. The command structure enables the modulation function to be accomplished using an already available modulation facility within engine controller 26 (laser control 28). No direct access is required tolaser drive circuit 30 byformat controller 22.
Claims (7)
- A color laser printer (12) for producing raster scan pixel images, including means for modulating edge pixels of an image to improve said image's resolution, said printer comprising:a laser engine (30, 32) for exposing an electrophotographic surface in accordance with applied modulation signals; andedge enhancement means (22, 24) for determining, for an image pixel that resides at an edge of an image, whether said image pixel is to be modified to improve resolution of said edge and if so, generating a said binary multi-bit command (RVDATA) indicative of a desired pixel modification;a laser engine controller (26, 28) for controlling said laser engine (30,32) to enable movement of a print media and a laser beam, said laser engine controller (26, 28) applying a modulation signal to said laser engine (30, 32) in response to a received binary multi-bit command, and said laser engine controller (26, 28) providing synchronization signals (PSYNC, LSYNC, PCLK) indicative of a color and a print position of said laser engine to said edge enhancement means (22, 24) for successive color print operations;wherein said edge enhancement means (22, 24) transmits said multi-bit command (RVDATA) to said laser engine controller (26, 28) in response to said synchronization signals.
- The color laser printer (12) as recited in claim 1 wherein said laser engine controller (26, 28) generates variable duration modulation signals in response to said binary multi-bit commands from said edge enhancement means (22, 24).
- The color laser printer as recited in claim 2 wherein said edge enhancement means (22, 24) indicates one of a plurality of pixel sizes and orientations that will improve said image edge resolution by generating a said binary multi-bit command (RVDATA) that is uniquely related to a said indication, said laser engine controller (26, 28) responding to said binary multi-bit command (RVDATA) by generating a uniquely related variable duration modulation signal.
- The color laser printer (12) as recited in claim 3 further comprising:format control means (22) associated with said edge enhancement means (22, 24) for providing as an output to said laser engine controller (26, 28), pixel data representative of a bit map of an image to be printed.
- The color laser printer (12) as recited in claim 4 wherein said laser engine controller (26, 28) provides clock signals to said format control means (22), said format control means (22) responding by returning said clock signals to said controller means (26, 28), using said clock signals to time an output of pixel data signals to said laser engine controller (26, 28), and further using said clock signals to time an output of a said binary multi-bit command (RVDATA) that relates to a state of a said pixel data output from said format control means (22).
- The color laser printer (12) as recited in claim 5 wherein said laser engine (30, 32) includes laser modulation circuitry (30) that is only accessible through said laser engine controller (26, 28).
- A method for improving color image edge resolution in a raster scan pixel image color laser printer (12) comprising edge enhancement means, an engine controller and a laser engine, wherein the following steps are carried out for successive color print operations in response to synchronization signals sent from the engine controller to the edge enhancement means and being indicative of a color and a print position of the laser engine;the edge enhancement means determining for an image pixel that resides at an edge of an image if resolution of said edge can be improved by modifying a configuration of said image pixel;if yes, generating a binary multi-bit command (RVDATA) indicative of one of a plurality of unique pixel configurations;generating a signal in response to a said binary multi-bit command that exhibits a unique, timed relationship to a pixel time period; andthe laser engine modulating a laser (32) in response to said generated signal so as to produce a light pulse that exposes an electrophotographic surface in a manner to achieve said unique pixel configuration.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/010,026 US5392061A (en) | 1993-01-25 | 1993-01-25 | Pixel resolution enhancement employing encoded dot size control |
US10026 | 1993-01-25 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0608474A2 EP0608474A2 (en) | 1994-08-03 |
EP0608474A3 EP0608474A3 (en) | 1995-02-15 |
EP0608474B1 true EP0608474B1 (en) | 1999-09-22 |
Family
ID=21743400
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP93112664A Expired - Lifetime EP0608474B1 (en) | 1993-01-25 | 1993-08-06 | Pixel resolution enhancement employing encoded dot size control |
Country Status (4)
Country | Link |
---|---|
US (1) | US5392061A (en) |
EP (1) | EP0608474B1 (en) |
JP (1) | JPH071760A (en) |
DE (1) | DE69326534T2 (en) |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH07107280A (en) * | 1993-10-06 | 1995-04-21 | Matsushita Electric Ind Co Ltd | Picture forming device |
JPH089135A (en) * | 1994-06-14 | 1996-01-12 | Minolta Co Ltd | Printer |
US6678426B1 (en) | 1997-05-13 | 2004-01-13 | Hewlett-Packard Development Company, L.P. | Programmable mapping of lower resolution digital data to a higher resolution for output on a lower resolution device |
DE69733133T2 (en) * | 1997-07-29 | 2006-02-02 | Esko-Graphics A/S | Resolution improvement on a picture setter |
US6135655A (en) * | 1997-10-14 | 2000-10-24 | Hewlett-Packard Company | Multipixel dots in monochrome drop-on-demand printing |
US6295078B1 (en) | 1999-05-26 | 2001-09-25 | Hewlett-Packard Company | Methods of providing lower resolution format data into a higher resolution format |
US6476844B1 (en) | 2000-10-12 | 2002-11-05 | Lexmark International, Inc. | Method and apparatus for electrophotographic laser video modulation and decode for spot fidelity |
US6593066B2 (en) * | 2001-02-28 | 2003-07-15 | Creo Il. Ltd. | Method and apparatus for printing patterns on substrates |
US7483167B2 (en) * | 2003-08-27 | 2009-01-27 | Marvell International Ltd. | Image forming apparatus for identifying undesirable toner placement |
US7733532B2 (en) | 2004-10-27 | 2010-06-08 | Marvell International Technology Ltd. | Laser print apparatus with dual halftones |
US7697169B2 (en) | 2004-10-29 | 2010-04-13 | Marvell International Technology Ltd. | Laser print apparatus with toner explosion compensation |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4586037A (en) * | 1983-03-07 | 1986-04-29 | Tektronix, Inc. | Raster display smooth line generation |
US4544264A (en) * | 1984-05-17 | 1985-10-01 | International Business Machines Corporation | Fine line print enhancement |
US4780711A (en) * | 1985-04-12 | 1988-10-25 | International Business Machines Corporation | Anti-aliasing of raster images using assumed boundary lines |
US4847641A (en) * | 1988-08-16 | 1989-07-11 | Hewlett-Packard Company | Piece-wise print image enhancement for dot matrix printers |
US4933689A (en) * | 1989-10-25 | 1990-06-12 | Hewlett-Packard Company | Method and apparatus for print image enhancement |
US5029108A (en) * | 1990-09-24 | 1991-07-02 | Destiny Technology Corporation | Edge enhancement method and apparatus for dot matrix devices |
DE69222785T2 (en) * | 1991-01-14 | 1998-05-07 | Seiko Epson Corp | Method for generating point-organized image data, and device for modulating a laser beam with this data |
US5249242A (en) * | 1991-12-23 | 1993-09-28 | Adobe Systems Incorporated | Method for enhancing raster pixel data |
-
1993
- 1993-01-25 US US08/010,026 patent/US5392061A/en not_active Expired - Fee Related
- 1993-08-06 DE DE69326534T patent/DE69326534T2/en not_active Expired - Fee Related
- 1993-08-06 EP EP93112664A patent/EP0608474B1/en not_active Expired - Lifetime
-
1994
- 1994-01-25 JP JP6023105A patent/JPH071760A/en active Pending
Also Published As
Publication number | Publication date |
---|---|
DE69326534T2 (en) | 2000-05-04 |
EP0608474A3 (en) | 1995-02-15 |
JPH071760A (en) | 1995-01-06 |
US5392061A (en) | 1995-02-21 |
DE69326534D1 (en) | 1999-10-28 |
EP0608474A2 (en) | 1994-08-03 |
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